At the end of June an American flag was hoisted on Collier's Island in Assawoman Bay.

It's a patriotic sight, but one that raises concerns for the Maryland Coastal Bays Program. That island was created this past winter for the birds, not the people, and while human activity is fine this year, boaters may need to be more careful in the future.

"It takes the birds a while to find (an island) and to feel comfortable," Co-Executive Director Roman Jesien said. "My concern is in coming years, people will think this island is a place to tie their boat up and party."

Bare, sandy islands are good nesting ground for terns and other migratory species, but they are rare in Maryland. And this year the Maryland Coastal Bays Program has seen a sharp drop in royal tern populations.

While normally the program finds more than 200 royal terns, this year they only found 44, and it is because of habitat loss, Jesien said. The program hopes Collier's will become new nesting ground from which the birds can rebuild.

For this year at least, it's fine for people to explore and hang out on the newly created island because birds haven't discovered it yet. When migratory birds that need sandy islands start nesting, boaters will be asked to use caution on the island.

"If it's being used by a whole lot of folks, the birds don't get a chance to establish nests," Jesien said. "It really defeats the purpose of creating those islands."

If an endangered species nests on the island, the island will be closed to the public, Jesien said.

A few miles south of Collier's, an endangered species is nesting on an island near Sixth Street. It's the only black skimmer nest in Maryland, and scientists fear it could be washed away.

July 4 weekend posed a daunting situation for the birds. A full moon brought the high tide close to the nest, and a busy weekend promised plenty of traffic from large boats, with threatening wakes.

"The island is very small and the beach is very limited," Maryland Department of Natural Resources scientist Dave Brinker said. "They get squeezed."

Despite concerns, the nest of six adults and seven juveniles on the island all survived the weekend, according to Jesien.

The birds will be at an increased risk again during the new and full moons July 16 and 30. Boaters are asked to use caution and slow down in front of the island to protect the birds.